Those who work on automotive transmissions, be they individual drivers or mechanics in established repair facilities, are very familiar with the procedures and problems involved in changing or replacing the clutch assembly n the manual transmission portion of the driving system for automotive vehicles. Under presently known arrangements, to change a clutch assembly or to replace a worn member, it is necessary to elevate the vehicle, place appropriate jacks or supporting devices beneath the transmission, as well as the drive shaft from the transmission to the driving wheels. It is then necessary to disassemble the connection between the vehicle engine portion of the transmission and the mechanism which rotates the drive shaft. This requires, among other things, that the transmission cover be removed, the clutch fork be disengaged from the clutch, and the drive shaft then be pulled back from the transmission assembly and lowered to a support. Then, it is necessary to pull out the clutch assembly, disassemble it and replace the friction plate or other element within the clutch assembly. Such assemblies are known from the McLeod patents which are dominant in this area. They consist of a front plate and a back plate and two clutch friction plates which are positioned back to back. Each clutch friction plate contains a circular element having a hub and openings in its surface for a plurality of helical springs which are utilized in the shifting of the transmission to alternately engage and disengage the friction clutch to permit the shifting of the gears. Each friction plate also carries four extending arms on its outer surface which contain four pads which, on the plate surface facing the engine can be engaged with the driving plate from the engage, and on the other plate surface facing the rear of the vehicle to transfer the power from the engine to the drive shaft via the two plates. The pads are mounted on the exterior surface of each friction plate and on what might be referred to as angled, L-shaped, spoon-shaped elements, each element terminating in a portion to which a pad is attached and which pad per se can be replaced as the clutch wears out, which angled L-shaped arm is bolted to its plate in each instance. It may be appropriate to again review the structure of the friction plate assembly bearing the pads which basically comprises the central part of the clutch system in a manual transmission system. There are two center plates, which have been discussed before, each of which contains a plurality of friction pads on each outer surface. Each friction pad bearing plate itself being a segmented unit comprising eight trapezoidal-type plates, each of which has attached to it, by rivets, the pads and their respective supporting arms. There is also a front plate which encompasses the outer central or hub portion of one pad bearing plate surface having eight apertures therein for the helical springs which are contained with the clutch. The front plate has a circular opening therein having no extrusions or obtrusions therein. The rear plate consists of a circular plate which encompasses the central portion of the other pad bearing plate surface having therein eight recesses for the helical springs mentioned before. The rear plate has a central opening which contains a plurality of grooves and lands which correspond to the grooves and lands in the driven shaft. Thus, it is readily apparent that under the present status of the clutch relationship with the drive shaft of a vehicle, that the grooves and lands on the interior surface of the rear plate must coincide with the grooves and lands on the drive shaft. Those of knowledge, either be it practical or theoretical, realize that the transmission contains a drive mechanism which can be engaged by the friction pads on the surface of the rear plate carrying the drive shaft but are also controlled by the other plate with its pads in its movement in and out of contact with the fly wheel by the pressure plate on the exterior side of the clutch assembly.
Another assembly related to the foregoing McLeod type clutch comprises only a single clutch friction plate comprising a circular element with a central hub opening and two outer surfaces, the plate having openings and through the outer surfaces for a plurality of helical springs which are utilized in the shifting of the transmission to alternately engage and disengage the friction clutch to permit the shifting of gears. The friction plate carries four extending arms on each of its outer surfaces. Each arm on the surface contains a pad which, on the plate surface facing the engine can be engaged with the driving plate in the engine and on the plate surface facing the rear of the vehicle can transfer the power from the engine via the plate to the friction plate on the drive shaft. Each arm on both exterior surfaces of the single friction plate consists of an angled, spoon-shaped element terminating in the portion to which the pad is attached and which pad per se can be replaced as the clutch wears out. This single plate assembly includes a front circular plate which encompasses the central or hub portion of one of the outer surfaces of said single plate, the front plate having eight apertures therein for the helical springs which are contained in said apertures. This assembly also comprises a rear circular plate having eight recesses therein and which encompasses the central portion of the single pad bearing plate and has eight recesses therein to receive the aforementioned helical springs. The rear plate has a central opening as a hub which contains a plurality of lands and grooves which correspond in size and spacing to the lands and grooves on the drive shaft.